Portable electronic devices such as smart cards are known. These smart cards conventionally include an electronic assembly capable of at least elaborating information. The electronic assembly is formed of a plurality of components which are arranged next to each other in the plane of the smart card and which are embedded in a plastic material which provides the smart card with a shape and high mechanical resistance. In most cases, these smart cards are thin and are not intended to be subject to high bending angles in normal conditions of use. Consequently, the electronic components confined in the body of the smart card are slightly deformed or not deformed at all and the homogeneity of the connection between the components and the plastic material of which the smart card body is made is not at risk.
The situation is quite different when the flexible portable electronic device is intended to be subjected to high bending angles, for example because it is wound around a user's wrist. Such flexible portable electronic devices, for example wristwatches, include an electronic assembly for elaborating and where necessary displaying information, which is formed of an information display device, such as a liquid crystal display device, a flexible printed circuit which carries the integrated and discrete components required for the proper operation of the portable electronic device, and an electric power battery. These various electronic components generally take the form of broad, flat elements, arranged one on top of the other. They are over-moulded in a plastic material such as an elastomer, which gives the portable electronic device thickness and mechanical resistance.
It is clear that, when the portable electronic device is wound, the radius of curvature of the various electronic components which form the electronic assembly for processing information varies according to the position of each of the components in the stack of components. The lower the radius of curvature, the higher the angle of winding of the corresponding component will be. Differences in winding length may therefore be observed according to the position and length of the components. However, if the various electronic components are, for example, bonded over their entire surface, the differences in length must be compensated for by the elasticity of the electronic components and the bonds have to resist high shear stresses. If the elasticity of the electronic components is insufficient or if the bonds do not resist the stresses, the portable electronic device is liable to warp or delamination which leads to the destruction of the device.